Thin film battery device and method of formation

ABSTRACT

A thin film battery may include: a cathode current collector, the cathode current collector being disposed in a first plane; a device stack disposed on the cathode current collector, the device stack comprising an anode current collector, the anode current collector being disposed in a second plane, above the first plane; and a thin film encapsulant, the thin film encapsulant disposed above the device stack, wherein the thin film encapsulant comprises a first portion extending along a surface of the anode current collector and a second portion extending along a plurality of sides of the device stack, wherein the cathode current collector extends under the second portion of the thin film encapsulant and outside of the thin film encapsulant; and wherein the anode current collector extends under the first portion of the thin film encapsulant and outside of the thin film encapsulant.

RELATED APPLICATIONS

This Application claims priority to U.S. provisional patent applicationNo. 62/322,415, filed Apr. 14, 2016, entitled “Volume ChangeAccommodating TFE Materials,” and incorporated by reference herein inits entirety.

FIELD

The present embodiments relate to thin film encapsulation (TFE)technology used to protect active devices, and more particularly toencapsulating thin film battery devices.

BACKGROUND

In the fabrication of thin film batteries, patterning of devicestructures remains a challenge, for forming active regions of a device,or front-end, and for forming encapsulation portions of a device, orback-end.

In particular, for seamless integration into systems incorporating thinfilm batteries, a large benefit is the ability to form very thinbatteries. To this end, reduction of non-active materials such asencapsulation material is useful, so non-active portions of a thin filmbattery add minimally to the overall size of the battery. Known methodsof packaging energy storage devices, such as thin film batteries,include pouching, lamination, and the like. These methods add anundesirable amount of weight and volume to the device being packaged, orencapsulated. Thin film encapsulation (TFE) approaches for protectingactive components of a thin film battery offer a potentially simplifiedmanner of encapsulation, with minimum material and volume addition tothe system. Notably, TFE approaches for these types of devices, such asthin film batteries, are far more challenging for several reasons.Firstly, accommodation of volume changes is useful, adding potentialstress to a thin film encapsulant region during device operation.Secondly, a main function of the TFE is to provide good oxidantpermeation barrier properties. Moreover, a TFE may be used encapsulatedevice structures including a larger topography variation. At thepresent, good TFE fabrication methods and the resulting devicearchitectures are lacking for providing robust and consistent long-termoperation of these devices.

With respect to these and other considerations the present disclosure isprovided.

BRIEF SUMMARY

In one embodiment, a thin film battery may include a cathode currentcollector, the cathode current collector being disposed in a firstplane; a device stack disposed on the cathode current collector, wherethe device stack comprises an anode current collector, where the anodecurrent collector is disposed in a second plane, above the first plane.The thin film battery may further include a thin film encapsulant, wherethe thin film encapsulant is disposed above the device stack, whereinthe thin film encapsulant comprises a first portion extending along asurface of the anode current collector and a second portion extendingalong a plurality of sides of the device stack. The cathode currentcollector may extend under the second portion of the thin filmencapsulant and outside of the thin film encapsulant, and the anodecurrent collector may extend under the first portion of the thin filmencapsulant and outside of the thin film encapsulant.

In another embodiment, a method of forming a thin film battery mayinclude depositing a cathode current collector on a substrate in a firstplane and forming a device stack on the cathode current collector, wherethe device stack comprises an anode current collector. The anode currentcollector may be disposed in a second plane above the first plane. Themethod may include forming a thin film encapsulant above the devicestack, wherein the thin film encapsulant comprises a first portionextending along a surface of the anode current collector and a secondportion extending along a side of the device stack. The cathode currentcollector may extend under the device stack, under the second portion ofthe thin film encapsulant and outside of the thin film encapsulant. Theanode current collector may extend under the first portion of the thinfilm encapsulant and outside of the thin film encapsulant.

In another embodiment, a method of encapsulating a thin film battery mayinclude providing an active device region on a substrate base, whereinthe active device region comprises a cathode current collector and adevice stack. The device stack may be disposed on a portion of thecathode current collector and include an anode current collector. Themethod may also include forming a thin film encapsulant above the devicestack, wherein the thin film encapsulant comprises a first portionextends along a surface of the anode current collector and a secondportion extending along a side of the device stack. The cathode currentcollector may extend under the device stack, under the second portion ofthe thin film encapsulant and outside of the thin film encapsulant, andthe anode current collector may extend under the first portion of thethin film encapsulant and outside of the thin film encapsulant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a thin film battery according to various embodimentsof the disclosure;

FIG. 1B provides one embodiment of a thin film battery, arrangedaccording to embodiments of the disclosure;

FIGS. 2A-2J illustrates a cross-sectional view of a thin film battery atvarious stages of assembly; and

FIG. 3 shows an exemplary process flow according to embodiments of thedisclosure.

DETAILED DESCRIPTION

The present embodiments will now be described more fully hereinafterwith reference to the accompanying drawings, where some embodiments areshown. The subject matter of the present disclosure may be embodied inmany different forms and are not to be construed as limited to theembodiments set forth herein. These embodiments are provided so thisdisclosure will be thorough and complete, and will fully convey thescope of the subject matter to those skilled in the art. In thedrawings, like numbers refer to like elements throughout.

The present embodiments are related to thin film encapsulant structuresand methods, where the thin film encapsulant is used to minimize ambientexposure of active devices. The present embodiments provide novelstructures and materials combinations for thin film devices encapsulatedusing thin film encapsulation.

Examples of active devices include electrochemical devices includeelectrochromic windows and thin film batteries wherein the activecomponent materials are highly sensitive/reactive to moisture or otherambient materials. To this end, known electrochemical devices such asthin film batteries may be provided with encapsulation to protect theactive component materials.

In various embodiments, a thin film device such as a thin film batteryand techniques for forming a thin film battery are provided with a novelarchitecture including an encapsulant material. The thin film batterymay include a layer stack composed of active layers, as well as the thinfilm encapsulant, where the thin film encapsulate also constitutes amultilayer structure.

In various embodiments novel combinations of thin film deposition andpatterning operations is established, for formation of an active deviceregion, a thin film encapsulant, or a combination of active deviceregion and thin film encapsulant.

According to various embodiments, techniques are provided for formingthin film batteries exhibiting an improvement in the structure, the easeof manufacturing, performance, or a combination of these factors, ascompared to known thin film batteries. Various considerations may affectthe design of a thin film battery. A non-exhaustive list of factorsincludes the ability of the battery to accommodate local volume changeswithin specific regions of the thin film battery taking place duringoperation of a battery; protection from oxidative permeation; andability to form a device accounting for large variations in topography.Further factors include the ability to limit the non-active material ina thin film battery to an acceptable level; the ability to form a thinfilm battery having an acceptable portion of non-active material withinthe device regions; and ability to manufacture a thin film battery usingcost-effective techniques. In particular embodiments disclosed herein,the formation of thin film encapsulation is integrated with theformation of active device regions of a thin film battery in a novelmanner enabling a more robust architecture for operation and stabilityof the thin film battery.

FIG. 1A illustrates a thin film battery 100 according to variousembodiments of the disclosure. The thin film battery 100 may include asubstrate 102. In some embodiments, the substrate 102 may be considereda substrate base forming a part of the thin film battery 100 or mayserve as a support for the thin film battery. The substrate 102 may bean insulator, semiconductor, or a conductor, depending upon the targetedelectrical properties of the exterior surfaces. More specifically, thesubstrate 102 may be made from a ceramic, metal or glass, such as, forexample, aluminum oxide, silicate glass, or even aluminum or steel,depending on the application.

As shown in FIG. 1A, the thin film battery 100 may include a cathodecurrent collector 104, where the cathode current collector 104 isdisposed as a layer on the substrate 102 in a first plane (parallel tothe X-Y plane of the Cartesian coordinate system shown). The cathodecurrent collector 104 may be a known cathode current collector such as ametal or metal alloy. The thin film battery 100 may include a devicestack 105, where the device stack 105 is disposed on the cathode currentcollector 104. The device stack 105 may include an anode currentcollector 108, where the anode current collector 108 is disposed in anon-coplanar configuration in a second plane, above the first plane ofthe cathode current collector 104. The device stack 105 may also includea portion 106 composed of additional components as in known thin filmbatteries, including cathode, electrolyte, and anode in some cases. Thethin film battery 100 may further include a thin film encapsulant 110disposed above the device stack 105. The thin film encapsulant 110 mayserve to encapsulate at least a portion of the device stack 105 toprotect the thin film battery 100. As detailed below, in variousembodiments, the thin film encapsulant 110 may include a plurality oflayers. As shown in FIG. 1A, the thin film encapsulant 110 may bepatterned to define various regions where no thin film encapsulantmaterial is present. For example, in region 120 no thin film encapsulantmaterial is present, providing a region where a contact to the thin filmbattery 100 may be formed. While not shown, contact material, such as ametal, such as silver, may be provided in the region 120. This contactmaterial provides a conductive path for forming an external contact tothe cathode side of the thin film battery 100. Additionally, in region122 no thin film encapsulant material is present, providing a regionwhere a contact to the thin film battery 100 may be formed. This contactprovides a conductive path for forming an external contact to the anodeside of the thin film battery 100.

In various embodiments, the thin film encapsulant 110 may be arranged asa thin film encapsulant including a first portion extending along asurface of the anode current collector 108 and a second portionextending along a side of the device stack 105. In particular, as shownin FIG. 1A, the thin film encapsulant 110 may include a portion 114extending over the surface 112 of the anode current collector 108, and aportion 116 extending along a side 115 of the device stack 105. As such,the thin film encapsulant 110 provides at least partial encapsulation ofthe device stack 105. For example, while the side 115 is shown asencapsulated, encapsulation also extends to the right side of devicestack 105 (not shown).

Turning now to FIG. 1B, there is shown a thin film battery 150, wherethe thin film battery 150 may be a variant of the thin film battery 100.As shown, the thin film battery 150 may include a device stack 105,including a cathode 152, where the cathode 152 is disposed on thecathode current collector 104; and a solid state electrolyte 154, wherethe solid state electrolyte 154 is disposed on the cathode 152 and underthe anode current collector 108. In this variant, the thin filmencapsulant 110 includes a plurality of layers as shown. In particular,the thin film encapsulant 110 may include a layer stack including alayer 160, a layer 162, a layer 164, a layer 166, a layer 168, and alayer 170. These layers in the thin film encapsulant 110 may servemultiple functions, including protecting the device stack 105 from beingattacked by oxygen, water, or other species tending to damage the thinfilm battery 100. To this end, the thin film encapsulant 110 mayencapsulate the cathode 152, the solid state electrolyte 154, and anodecurrent collector 108 on the side 115 (see FIG. 1A) of the device stack105, as well as to the right side (not shown) of the cathode 152, thesolid state electrolyte 154, and anode current collector 108.Accordingly, the thin film encapsulant 110 includes a first portionextending along a surface of the anode current collector 108 and asecond portion extending along a side or sides of the device stack 105,including the side 115 and other side to the right (not shown).

The thin film encapsulant 110 may further act to accommodate volumechanges occurring in the device stack 105 when the thin film battery 100is charged and discharged. For example, in embodiments where the thinfilm battery is a lithium battery, the cathode 152 may be a LiCoO₂material including lithium, where the lithium diffuses back and forthbetween the cathode 152 and the anode current collector 108 duringcharging and discharging. The lithium may diffuse through the solidstate electrolyte 154, where the solid state electrolyte 154 may be aknown lithium phosphorous oxynitride (LiPON) material conducting thelithium between the cathode 152 and an anode region (not specificallyshown) in the device stack 105. As such the lithium may tend toaccumulate in a layer in the anode region during charging or to evacuatethe anode region during discharging, where an effective layer thicknessin the anode region may change by several micrometers or more during thecharging and discharging.

At least one of the layers of the thin film encapsulant 110 in theembodiment of FIG. 1B may be a soft and pliable polymer layer useful foraccommodating such volume changes in the device stack 105. In specificembodiments, the term “polymer layer” may refer to just one polymerlayer or to a polymer layer stack including multiple sub-layers ofdifferent polymers, where at least one sub-layer is soft and pliable. Asoft and pliable polymer layer, either arranged as just one layer, or asa layer stack of sub-layers, may be characterized by a relatively lowerelastic modulus, relatively high elongation to break, and relatedproperties. Examples of materials having low elastic modulus includesilicone: hardness of ˜A40 Shore A, Young's Modulus of ˜0.9 Kpsi or ˜6.2MPa; Parylene-C: hardness of ˜Rockwell R80, Young's Modulus of ˜400 Kpsior ˜2.8 GPa; KMPR: Young's Modulus of ˜1015 Kpsi or ˜7.0 GPa; polyimide:hardness of D87 Shore D, Young's Modulus of ˜2500 Kpsi or ˜17.2 GPa.Examples of a relatively larger elongation to break include: silicone,100 to 210%; Parylene-C, 200%; polyimide, 72%; acrylic, 2.0 to 5.5%;epoxy, 3 to 6%.

More particularly, as used herein, a “soft and pliable” material mayrefer to a material having an elastic (Young's) modulus less than 20GPa, for example, while a “rigid material.” such as a rigid metal layeror rigid dielectric layer, may have an elastic modulus greater than 20GPa. Other characteristic properties associated with a soft and pliablematerial include a relatively high elongation to break, such as 70% orgreater for at least one polymer layer of the thin film encapsulant. Insome examples, such as silicone, a soft and pliable material may have anelongation to break up to 200% or greater.

As an example, the layer 160 may be a soft and pliable polymer, whilethe layer 162 may be a rigid material, such as a rigid metal or a rigiddielectric, such as silicon nitride. The layer 162 may serve thefunction of preventing oxygen and water diffusion into the device stack105. The sequence layers of a polymer layer and a rigid dielectric layermay be repeated through the thin film encapsulant 110. In other words,the thin film encapsulant 110 may include at least one dyad, wherein agiven dyad includes a soft and pliable polymer layer, and a rigiddielectric layer disposed adjacent the polymer layer. In particularembodiments, the layer 164 may be a polymer layer such as a soft andpliable polymer layer, the layer 166 a rigid dielectric layer or rigidmetal layer, the layer 168 a soft and pliable polymer layer, and thelayer 170 a rigid dielectric layer or rigid metal layer. While the thinfilm encapsulant 110 of FIG. 1B includes four dyads, in otherembodiments a thin film encapsulant may include a greater number or alesser number of dyads.

As further illustrated in FIG. 1B, the thin film encapsulant 110 may bearranged as a thin film encapsulant where a polymer layer, and a rigiddielectric layer or a rigid metal layer, extend in a non-planar fashionon the device stack 105. In particular the multiple soft and pliablepolymer layers and rigid dielectric layers of thin film encapsulant 110may be arranged along the surface 112 (see FIG. 1A) of the anode currentcollector 108. These layers may lie parallel to the X-Y plane(horizontally) in the portion 114, while these same layers extend morevertically along the side of the device stack 105 in the portion 116, asshown.

FIGS. 2A-2J illustrates a cross-sectional view of a thin film battery atvarious stages of assembly. In this example, the final structure 220illustrated at FIG. 2J may represent a portion of the thin film battery150 of FIG. 1B. A particular feature of the embodiments reflected inFIGS. 2A-2J is a method providing the integration of a thin filmencapsulant with the formation of a non-coplanar configuration ofcathode current collector and anode current collector layers. The flowof operations shown in FIGS. 2A-2J has the advantage of providing astraightforward process flow while utilizing substrate area in anefficient manner.

Turning now to FIG. 2A, there is shown an instance where a series oflayers are disposed on the substrate 102. In particular, the cathodecurrent collector 104, cathode layer 152A, solid state electrolyte layer154A, and anode current collector layer 108A are formed in a layersequence above the substrate 102. The cathode current collector 104,cathode layer 152A, solid state electrolyte layer 154A, and anodecurrent collector layer 108A may be deposited in a sequence of blanketdepositions in various embodiments. Other known operations for formingan active device region of a thin film battery may be performed, such asannealing the substrate after the depositing the cathode, and beforedepositing the solid state electrolyte. Additionally, in some variants,a distinct anode layer (not shown) may be formed by depositing a lithiumanode layer after the depositing the solid state electrolyte layer 154Aand before the depositing the anode current collector layer 108A.

In some embodiments, the individual layers may be deposited using anycombination of physical vapor deposition, chemical vapor deposition, andliquid deposition techniques. The layer thickness of these layers may bein accordance with thicknesses for known thin film batteries.

Turning now to FIG. 2B there is shown a subsequent instance where thelayers shown in FIG. 2A, save the cathode current collector 104, havebeen patterned to form a device stack 105. In various embodiments, thestructure of FIG. 2B may be formed by patterning the cathode layer 152A,the solid state electrolyte layer 154A, and the anode current collectorlayer 108A to form the device stack 105 and to expose the cathodecurrent collector 104, forming the exposed surface 124, in a firstregion 202. In some embodiments, the device stack 105 may be formed byapplying a maskless etching process, such as laser etching to at leastone layer of the device stack 105. In other embodiments, at least one ofthe layers of the device stack 105 may be patterned using masking andetching as in know processes. The formation of the device stack 105 maytake place using any combination of maskless and masked patterningprocesses. In various embodiments the thickness of the device stack 105may range from 15 micrometers to 60 micrometers. The embodiments are notlimited in this context. In various embodiments, the patterning of thedevice stack 105 may be accomplished by using laser ablation of otherlaser processing as detailed below, with respect to patterning of a thinfilm encapsulant. In brief, select portions of a given layer of thedevice stack 105 may be etched using laser ablation where a laser israstered over the select portion of the layer to be etched for a giventime and number of repetitions to achieve a target etch depth. Etchingmay proceed from the top layer down, which layer may be the anodecurrent collector 108, where at the end of the ablation process, thelaser intensity is lowered to a level just below the ablation thresholdfor the cathode current collector 104. This lowering of the laserintensity allows removal of the remaining amount of the cathode 152 inthe select portion being etched, while not etching the cathode currentcollector 104.

In various embodiments, the formation of a thin film encapsulant such asthe thin film encapsulant 110 may take place in a series of operations,as detailed in FIG. 2C to FIG. 2J. Turning now to FIG. 2C there is showna subsequent instance involving the depositing of an initial polymerlayer, shown as layer 160, in blanket form directly on the anode currentcollector 160 as well as on the first region 202 of the cathode currentcollector 104. In particular embodiments, the initial polymer layer,layer 160, may be a soft and pliable polymer. The blanket deposition ofthe layer 160 may be performed in a manner where the layer 160 providesa conformal coat, so the side 115 of the device stack 105 is alsocoated. As such, the layer 160 may extend horizontally in some regionsand vertically in other regions.

In various embodiments, the layer 160 may include a plurality ofsub-layers, where different sub-layers are arranged to favorconformality or planarization effects. The choice of materials anddeposition methods for different sub-layers may be tailored to induceeither planarization or conformality. For example, a first sub-layer maybe more conformal to promote sidewall coverage in a giventopography—such as Parylene. The second sub-layer may be moreplanarizing for better next-layer deposition, e.g., spin/dip coatingmethod. The use of multiple sub-layers within a layer 160, as well asthe use of additional layers in a thin film encapsulant (see layer 162as discussed below), may generate additional benefits including improvedadhesion and mechanical properties, as well as limiting reactions inactive regions of a thin film battery.

Turning now to FIG. 2D there is shown a subsequent instance where afterdepositing the initial polymer layer, patterning the initial polymerlayer, layer 160, is performed to form a patterned polymer layer over apatterned device stack, in other words, over the device stack 105. Thispatterning leaves the layer 160 along the side 115 of the device stack105 and exposes the cathode current collector 104 in a second region204, where the second region 204 is disposed in the first region 202. Invarious embodiments, the patterning the layer 160 may be performed by amasked patterning process or by a maskless patterning process. In eithera maskless or masked patterning process, the second region 204 islocated within the first region 202.

An advantage of using a maskless patterning process, such as laseretching, is the avoidance of complexity and costs associated with knownmasked patterning processes involving lithography and dry etching or wetetching. In this manner the complexities of lithography and etching, theconsumable costs, and device effects are eliminated. In addition, laserbased patterning allows device shape/design to be software recipe based,not depending upon physical masks, facilitating more rapid, flexible andsimpler design changes.

In various embodiments, laser patterning may be accomplished primarilyin two ways: using diffractive optics employing relatively high power tospread the laser beam over larger areas. This approach may be especiallysuitable for simple, easily repeated patterns not having fine patterndetails. Another type of laser patterning especially useful forpatterning thin film batteries according to the present embodiment isdirect laser ablation using a rastering approach. Simple and advancedgalvanometer based scanners may raster the laser beam to form morecomplex patterns, and are less limited by feature size and dimensions.To minimize patterning times, high repetition rate lasers (>1 MHz) maybe used in combination with polygon mirrors to accomplish high volumeproduction rates.

Pulse durations of picosecond and femtoseconds have been shown to beeffective for thin film ablation. The use of radiation wavelengths inthe ultraviolet (UV) range, green visible range, as well as infraredrange, including wavelengths ranging from 157 nm to 1024 nm, may beeffectively employed for patterning via laser ablation the layers ofthin film batteries of the present embodiments, including polymerlayers, rigid dielectric layers, and metal layers. While thin filmencapsulant materials are often transparent or semi-transparent, usablewavelengths may be more appropriate in the UV or green visible range.Most of the aforementioned short pulse lasers are DPSS (Diode pumpedsolid state) while some fiber based lasers are also contemplated for usein embodiments of the disclosure.

In various embodiments, the material of layer 160, such as a flexiblepolymer material, and the thickness of the layer 160 may be arranged toprovide benefits, such as accommodating deformation in the device stack105 taking place due to transport of lithium during charging anddischarging of a thin film battery to be formed. Turning now to FIG. 2Eand FIG. 2F, there are shown subsequent operations where a patterneddyad process is performed after the formation of the patterned initialpolymer layer as exemplified by FIG. 2D. A patterned dyad process mayinvolve depositing a blanket dyad composed of a rigid dielectric layerand a polymer layer on device stack 105 and on the cathode currentcollector 104. The patterned dyad process may further involve patterningthe blanket dyad to form a patterned thin film encapsulant over thepatterned device stack.

In the particular example of FIG. 2E, the first part of the patterneddyad process involves depositing the layer 162, where the layer 162 maybe a rigid dielectric layer, and depositing the layer 164, where thelayer 164 may be a polymer layer such as a soft and pliable polymerlayer. The layer 162 and layer 164 may be deposited as blanket layers,using a physical vapor deposition method, chemical vapor depositionmethod, liquid deposition method, other method, or any combination ofthese methods.

Turning now to FIG. 2F there is shown the subsequent instance wherepatterning of the layer 162 and layer 164 has been performed. Asillustrated the patterning has the effect to expose the cathode currentcollector 104 in a new region, shown as the region 206, where the newregion is disposed in the second region 204. Again, the region 206 maybe smaller than the second region 204. The patterning the layer 162 andthe layer 164 may be performed by a masked etching process or by amaskless etching process. In either a maskless or masked patterningprocess, the second region 204 is located within the first region 202.According to various embodiments, the patterning of the layer 162 andlayer 164 may be conducted just one patterning process where just oneetch operation takes place, and just one mask formation process is usedin the case of a masked patterning operation. Alternatively, thepatterning of the layer 162 and layer 164 may employ just one mask,while a plurality of etch operations are performed, such as twodifferent etch processes to etch the two different layers. Additionally,the patterning of the layer 162 and layer 164 may involve using a maskedpatterning process for one layer and a maskless patterning process forthe other layer. The embodiments are not limited in this context.

After performing a patterned dyad process, this process may be repeatedat least one time to generate a plurality of patterned dyads, accordingto some embodiments of the disclosure. Turning now to FIG. 2G and FIG.2H, there are shown subsequent operations where a second patterned dyadprocess is performed after the instance of FIG. 2F. The second patterneddyad process involves the deposition and patterning of the layer 166 andthe layer 168, in accordance with the deposition and patterningdescribed above with respect to FIGS. 2E and 2F.

In the particular example of FIG. 2G, the first part of the secondpatterned dyad process involves depositing the layer 166, where thelayer 166 may be a rigid dielectric layer, and depositing the layer 168,where the layer 168 may be a polymer layer such as a soft and. pliablepolymer layer. The layer 166 and layer 168 may be deposited as blanketlayers, as described above with respect to FIG. 2E.

Turning now to FIG. 2H there is shown the subsequent instance wherepatterning of the layer 166 and layer 168 has been performed. Asillustrated the patterning has the effect to expose the cathode currentcollector 104 in a new region, shown as the region 208, where the newregion is disposed in the second region 204. Again, the region 208 maybe smaller than the second region 204. The patterning the layer 162 andthe layer 164 may be performed as described above with respect to FIG.2F.

Turning now to FIG. 2I and FIG. 2J, there is shown the operationsperformed after the instance of FIG. 2H where a final layer, such as arigid dielectric layer may be deposited and patterned. Turning first toFIG. 2I, there is shown the instance after the depositing of a layer170, where the layer 170 may be a rigid dielectric layer. The layer 170may be deposited in blanket form by physical vapor deposition, chemicalvapor deposition, and liquid deposition techniques.

In various embodiments, the formation of a thin film encapsulant such asthe thin film encapsulant 110 may take place in a series of operations,as detailed in FIG. 2C to FIG. 2J. Turning now to FIG. 2I there is showna subsequent instance involving the depositing of the final rigiddielectric layer, shown as layer 170, in blanket form.

Turning now to FIG. 2J there is shown a subsequent instance where afterdepositing the final rigid dielectric layer, patterning the final rigiddielectric layer, layer 170, is performed. As illustrated the patterninghas the effect to expose the cathode current collector 104 in a newregion, shown as the region 210, where the new region is disposed in thesecond region 204. Again, the region 210 may be smaller than the secondregion 204.

While not explicitly shown in FIGS. 2A-2J, during the respectivepatterning operations, such as those depicted in FIG. 2D, FIG. 2F, FIG.2H, and FIG. 2J, the thin film battery may be patterned in other partsof the thin film battery. For example, returning to FIG. 1B, patterningmay be performed in the region 122 during the operations of FIG. 2D,FIG. 2F, FIG. 2H, and 2J, to form the structure shown, exposing asurface 126 of the anode current collector 108. Notably, in variousembodiment, the patterning operations generally shown in FIGS. 2B-2J maybe carried out in their entirety using laser etching, such as laserablation. By using laser ablation for the sequence of operations shown,a thin film battery may be formed in a streamlined manner, avoiding costand processing complexity associated with known lithographic and etchingprocesses.

In addition, and in accordance with embodiments of the disclosure, acontacting metal may be deposited on the region 210 to form a cathodecontact, as well as in the region 122 as shown in FIG. 1B.

Turning now to FIG. 3 there is shown an exemplary process flow 300according to embodiments of the disclosure. At block 302 a cathodecurrent collector is deposited on a substrate in a first plane. At block304, a device stack is formed on the cathode current collector, wherethe device stack includes an anode current collector disposed in asecond plane above the first plane. In various embodiments the devicestack may be formed by depositing a series of layers and patterning thelayers to form a patterned device stack. The patterned device stack maygenerate exposed regions of the cathode current collector, for example.At block 306, a thin film encapsulant is formed above the device stack.In some embodiments, the thin film encapsulant may be formed in a seriesof blanket depositions covering the patterned device stack and exposedregions, such as regions of the cathode current collector and anodecurrent collector. The thin film encapsulant may be patterned so as toform regions above the cathode current collector and the anode currentcollector. In particular embodiments, the thin film encapsulant may bepatterned to form a thin film encapsulant, wherein the thin filmencapsulant comprises a first portion extending along a surface of theanode current collector and a second portion extending along a side ofthe device stack. At the same time the cathode current collector mayextend under the device stack, under the second portion of the thin filmencapsulant and outside of the thin film encapsulant, and the anodecurrent collector may extend under the first portion of the thin filmencapsulant and outside of the thin film encapsulant.

There are multiple advantages provided by the present embodiments,including the ability to protect a device stack of a thin film batterywhile maximizing available substrate area, and the additional advantageof the ability to encapsulate a device stack in a manner accommodatingchanges in volume during operation of the thin film battery.

The present disclosure is not to be limited in scope by the specificembodiments described herein. Indeed, other various embodiments of andmodifications to the present disclosure, in addition to those describedherein, will be apparent to those of ordinary skill in the art from theforegoing description and accompanying drawings. Thus, such otherembodiments and modifications are intended to fall within the scope ofthe present disclosure. Furthermore, the present disclosure has beendescribed herein in the context of a particular implementation in aparticular environment for a particular purpose, while those of ordinaryskill in the art will recognize the usefulness is not limited theretoand the present disclosure may be beneficially implemented in any numberof environments for any number of purposes. Thus, the claims set forthbelow are to be construed in view of the full breadth and spirit of thepresent disclosure as described herein.

What is claimed is:
 1. A thin film battery, comprising: a cathodecurrent collector, the cathode current collector being disposed in afirst plane; a device stack disposed on the cathode current collector,the device stack comprising an anode current collector, the anodecurrent collector being disposed in a second plane, above the firstplane; and a thin film encapsulant, the thin film encapsulant disposedabove the device stack, wherein the thin film encapsulant comprises afirst portion extending along a surface of the anode current collectorand a second portion extending along a plurality of sides of the devicestack, wherein the cathode current collector extends under the secondportion of the thin film encapsulant and outside of the thin filmencapsulant, and wherein the anode current collector extends under thefirst portion of the thin film encapsulant and outside of the thin filmencapsulant.
 2. The thin film battery of claim 1, wherein the thin filmencapsulant comprises at least one dyad, wherein a dyad of the at leastone dyad comprises: a soft and pliable polymer layer; and a rigiddielectric layer or a rigid metal layer, the soft and pliable polymerlayer being disposed adjacent the rigid dielectric layer or rigid metallayer.
 3. The thin film battery of claim 1, wherein the device stackfurther comprises: a cathode, the cathode being disposed on the cathodecurrent collector; and a solid state electrolyte, the solid stateelectrolyte disposed on the cathode and under the anode currentcollector.
 4. The thin film battery of claim 3, wherein the thin filmencapsulant encapsulates the cathode, the solid state electrolyte andthe anode current collector on a side of the device stack.
 5. The thinfilm battery of claim 4, wherein the thin film encapsulant comprises apolymer layer and a rigid dielectric layer, the rigid dielectric layerbeing disposed adjacent the polymer layer, wherein the polymer layer andthe rigid dielectric layer extend in a non-planar fashion along thesurface of the anode current collector and along the side of the devicestack.
 6. The thin film battery of claim 2, wherein the thin filmencapsulant comprises a plurality of dyads, wherein the thin filmencapsulant further comprises a third region, wherein in the thirdregion, in at least one dyad of the plurality of dyads the soft andpliable polymer layer and the rigid dielectric layer extend in anon-planar fashion above the surface of the anode current collector. 7.The thin film battery of claim 1 further comprising a substrate base,the substrate base disposed adjacent the cathode current collector.
 8. Amethod of forming a thin film battery, comprising: depositing a cathodecurrent collector on a substrate in a first plane; forming a devicestack on the cathode current collector, the device stack comprising ananode current collector, the anode current collector being disposed in asecond plane above the first plane; and forming a thin film encapsulantabove the device stack, wherein the thin film encapsulant comprises afirst portion extending along a surface of the anode current collectorand a second portion extending along a side of the device stack, whereinthe cathode current collector extends under the device stack, under thesecond portion of the thin film encapsulant and outside of the thin filmencapsulant, and wherein the anode current collector extends under thefirst portion of the thin film encapsulant and outside of the thin filmencapsulant.
 9. The method of claim 8, wherein the forming the devicestack comprises: depositing a cathode layer on the cathode currentcollector; annealing the substrate after the depositing the cathodelayer; depositing a solid state electrolyte layer on the cathode layer;depositing the anode current collector on the solid state electrolytelayer; and before the forming the thin film encapsulant, patterning thecathode layer, the solid state electrolyte layer, and the anode currentcollector to form the device stack and to expose the cathode currentcollector in a first region.
 10. The method of claim 9, furthercomprising depositing a lithium anode layer after the depositing thesolid state electrolyte layer and before the depositing the anodecurrent collector.
 11. The method of claim 9, wherein the patterning thecathode layer, the solid state electrolyte layer, and the anode currentcollector comprises etching the cathode layer, the solid stateelectrolyte layer, and the anode current collector over the first regionusing laser ablation to selectively remove a portion of the cathodelayer, the solid state electrolyte layer, and the anode currentcollector.
 12. The method of claim 9, wherein the forming the thin filmencapsulant comprises forming a plurality of patterned dyads on theanode current collector, wherein a given patterned dyad of the pluralityof patterned dyads comprises a soft and pliable polymer layer and arigid dielectric layer.
 13. The method of claim 9, wherein the formingthe thin film encapsulant comprises: depositing a plurality of layers,wherein at least one layer comprises a soft and pliable polymer and atleast one layer comprises a rigid dielectric layer; and etching theplurality of layers using a plurality of etch operations.
 14. The methodof claim 9, wherein the forming the thin film encapsulant comprisesdepositing an initial polymer layer in blanket form directly on theanode current collector and on the first region of the cathode currentcollector, wherein the initial polymer layer comprises a soft andpliable polymer.
 15. The method of claim 14, further comprising: afterthe depositing the initial polymer layer: patterning the initial polymerlayer to form a patterned polymer layer over the device stack and toexpose the cathode current collector in a second region, the secondregion being disposed in the first region.
 16. The method of claim 15,further comprising performing, at least once, a patterned dyad processme, the patterned dyad process comprising: depositing a blanket dyadcomprising a rigid dielectric layer and a polymer layer on the devicestack and on the cathode current collector; and patterning the blanketdyad to form a patterned thin film encapsulant over the device stack andto expose the cathode current collector in a new region, the new regionbeing disposed in the second region.
 17. The method of claim 16, furthercomprising: depositing a final rigid dielectric layer in blanket form onthe patterned thin film encapsulant and on the new region of the cathodecurrent collector; and patterning the final rigid dielectric layer toform the thin film encapsulant, the thin film encapsulant being disposedover the device stack and exposing the cathode current collector in anew region, the new region being disposed in the second region.
 18. Amethod of encapsulating a thin film battery, comprising: providing anactive device region on a substrate base, wherein the active deviceregion comprises a cathode current collector and a device stack, thedevice stack being disposed on a portion of the cathode currentcollector and including an anode current collector; and forming a thinfilm encapsulant above the device stack, wherein the thin filmencapsulant comprises a first portion extending along a surface of theanode current collector and a second portion extending along a side ofthe device stack, wherein the cathode current collector extends underthe device stack, under the second portion of the thin film encapsulantand outside of the thin film encapsulant, and wherein the anode currentcollector extends under the first portion of the thin film encapsulantand outside of the thin film encapsulant.
 19. The method of claim 18,wherein the active device region further comprises a cathode and a solidstate electrolyte, wherein the providing the active device regioncomprises: depositing in blanket form the cathode current collector, thecathode, the solid state electrolyte, and the anode current collector;and patterning the anode current collector, the solid state electrolyte,and the cathode, wherein a portion of the cathode current collector isexposed.